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2024-10-21rust: helpers: remove unnecessary header includesTamir Duberstein
Commit e26fa546042a ("rust: kbuild: auto generate helper exports") removed the need for these by automatically generating the exports; it removed the explicit uses of `EXPORT_SYMBOL_GPL` but didn't remove the `#include <linux/export.h>`s. Signed-off-by: Tamir Duberstein <tamird@gmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org> Link: https://lore.kernel.org/r/20241009162553.27845-2-tamird@gmail.com [ Reworded title. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-21rust: exports: improve grammar in commentaryTamir Duberstein
Commit e26fa546042a ("rust: kbuild: auto generate helper exports") added an errant "the" where one was not needed; remove it. Signed-off-by: Tamir Duberstein <tamird@gmail.com> Reviewed-by: Dirk Behme <dirk.behme@gmail.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org> Link: https://lore.kernel.org/r/20241009162358.27735-1-tamird@gmail.com [ Reworded title. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-20drm/panic: allow verbose version checkThomas Böhler
Clippy warns about a reimplementation of `RangeInclusive::contains`: error: manual `!RangeInclusive::contains` implementation --> drivers/gpu/drm/drm_panic_qr.rs:986:8 | 986 | if version < 1 || version > 40 { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: use: `!(1..=40).contains(&version)` | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#manual_range_contains = note: `-D clippy::manual-range-contains` implied by `-D warnings` = help: to override `-D warnings` add `#[allow(clippy::manual_range_contains)]` Ignore this and keep the current implementation as that makes it easier to read. Fixes: cb5164ac43d0 ("drm/panic: Add a QR code panic screen") Reported-by: Miguel Ojeda <ojeda@kernel.org> Link: https://github.com/Rust-for-Linux/linux/issues/1123 Signed-off-by: Thomas Böhler <witcher@wiredspace.de> Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com> Link: https://lore.kernel.org/r/20241019084048.22336-8-witcher@wiredspace.de Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-20drm/panic: allow verbose boolean for clarityThomas Böhler
Clippy complains about a non-minimal boolean expression with `nonminimal_bool`: error: this boolean expression can be simplified --> drivers/gpu/drm/drm_panic_qr.rs:722:9 | 722 | (x < 8 && y < 8) || (x < 8 && y >= end) || (x >= end && y < 8) | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#nonminimal_bool = note: `-D clippy::nonminimal-bool` implied by `-D warnings` = help: to override `-D warnings` add `#[allow(clippy::nonminimal_bool)]` help: try | 722 | !(x >= 8 || y >= 8 && y < end) || (x >= end && y < 8) | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 722 | (y >= end || y < 8) && x < 8 || (x >= end && y < 8) | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ While this can be useful in a lot of cases, it isn't here because the line expresses clearly what the intention is. Simplifying the expression means losing clarity, so opt-out of this lint for the offending line. Fixes: cb5164ac43d0 ("drm/panic: Add a QR code panic screen") Reported-by: Miguel Ojeda <ojeda@kernel.org> Link: https://github.com/Rust-for-Linux/linux/issues/1123 Signed-off-by: Thomas Böhler <witcher@wiredspace.de> Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com> Link: https://lore.kernel.org/r/20241019084048.22336-7-witcher@wiredspace.de Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-20drm/panic: correctly indent continuation of line in list itemThomas Böhler
It is common practice in Rust to indent the next line the same amount of space as the previous one if both belong to the same list item. Clippy checks for this with the lint `doc_lazy_continuation`. error: doc list item without indentation --> drivers/gpu/drm/drm_panic_qr.rs:979:5 | 979 | /// conversion to numeric segments. | ^ | = help: if this is supposed to be its own paragraph, add a blank line = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#doc_lazy_continuation = note: `-D clippy::doc-lazy-continuation` implied by `-D warnings` = help: to override `-D warnings` add `#[allow(clippy::doc_lazy_continuation)]` help: indent this line | 979 | /// conversion to numeric segments. | ++ Indent the offending line by 2 more spaces to remove this Clippy error. Fixes: cb5164ac43d0 ("drm/panic: Add a QR code panic screen") Reported-by: Miguel Ojeda <ojeda@kernel.org> Link: https://github.com/Rust-for-Linux/linux/issues/1123 Signed-off-by: Thomas Böhler <witcher@wiredspace.de> Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com> Link: https://lore.kernel.org/r/20241019084048.22336-6-witcher@wiredspace.de [ Reworded to indent Clippy's message. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-20drm/panic: remove redundant field when assigning valueThomas Böhler
Rust allows initializing fields of a struct without specifying the attribute that is assigned if the variable has the same name. In this instance this is done for all other attributes of the struct except for `data`. Clippy notes the redundant field name: error: redundant field names in struct initialization --> drivers/gpu/drm/drm_panic_qr.rs:495:13 | 495 | data: data, | ^^^^^^^^^^ help: replace it with: `data` | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#redundant_field_names = note: `-D clippy::redundant-field-names` implied by `-D warnings` = help: to override `-D warnings` add `#[allow(clippy::redundant_field_names)]` Remove the redundant `data` in the assignment to be consistent. Fixes: cb5164ac43d0 ("drm/panic: Add a QR code panic screen") Reported-by: Miguel Ojeda <ojeda@kernel.org> Link: https://github.com/Rust-for-Linux/linux/issues/1123 Signed-off-by: Thomas Böhler <witcher@wiredspace.de> Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com> Link: https://lore.kernel.org/r/20241019084048.22336-5-witcher@wiredspace.de [ Reworded to add Clippy warning like it is done in the rest of the series. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-20drm/panic: prefer eliding lifetimesThomas Böhler
Eliding lifetimes when possible instead of specifying them directly is both shorter and easier to read. Clippy notes this in the `needless_lifetimes` lint: error: the following explicit lifetimes could be elided: 'b --> drivers/gpu/drm/drm_panic_qr.rs:479:16 | 479 | fn new<'a, 'b>(segments: &[&Segment<'b>], data: &'a mut [u8]) -> Option<EncodedMsg<'a>> { | ^^ ^^ | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_lifetimes = note: `-D clippy::needless-lifetimes` implied by `-D warnings` = help: to override `-D warnings` add `#[allow(clippy::needless_lifetimes)]` help: elide the lifetimes | 479 - fn new<'a, 'b>(segments: &[&Segment<'b>], data: &'a mut [u8]) -> Option<EncodedMsg<'a>> { 479 + fn new<'a>(segments: &[&Segment<'_>], data: &'a mut [u8]) -> Option<EncodedMsg<'a>> { | Remove the explicit lifetime annotation in favour of an elided lifetime. Fixes: cb5164ac43d0 ("drm/panic: Add a QR code panic screen") Reported-by: Miguel Ojeda <ojeda@kernel.org> Link: https://github.com/Rust-for-Linux/linux/issues/1123 Signed-off-by: Thomas Böhler <witcher@wiredspace.de> Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com> Link: https://lore.kernel.org/r/20241019084048.22336-4-witcher@wiredspace.de Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-20drm/panic: remove unnecessary borrow in alignment_patternThomas Böhler
The function `alignment_pattern` returns a static reference to a `u8` slice. The borrow of the returned element in `ALIGNMENT_PATTERNS` is already a reference as defined in the array definition above so this borrow is unnecessary and removed by the compiler. Clippy notes this in `needless_borrow`: error: this expression creates a reference which is immediately dereferenced by the compiler --> drivers/gpu/drm/drm_panic_qr.rs:245:9 | 245 | &ALIGNMENT_PATTERNS[self.0 - 1] | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: change this to: `ALIGNMENT_PATTERNS[self.0 - 1]` | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow = note: `-D clippy::needless-borrow` implied by `-D warnings` = help: to override `-D warnings` add `#[allow(clippy::needless_borrow)]` Remove the unnecessary borrow. Fixes: cb5164ac43d0 ("drm/panic: Add a QR code panic screen") Reported-by: Miguel Ojeda <ojeda@kernel.org> Link: https://github.com/Rust-for-Linux/linux/issues/1123 Signed-off-by: Thomas Böhler <witcher@wiredspace.de> Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com> Link: https://lore.kernel.org/r/20241019084048.22336-3-witcher@wiredspace.de Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-20drm/panic: avoid reimplementing Iterator::findThomas Böhler
Rust's standard library's `std::iter::Iterator` trait provides a function `find` that finds the first element that satisfies a predicate. The function `Version::from_segments` is doing the same thing but is implementing the same logic itself. Clippy complains about this in the `manual_find` lint: error: manual implementation of `Iterator::find` --> drivers/gpu/drm/drm_panic_qr.rs:212:9 | 212 | / for v in (1..=40).map(|k| Version(k)) { 213 | | if v.max_data() * 8 >= segments.iter().map(|s| s.total_size_bits(v)).sum() { 214 | | return Some(v); 215 | | } 216 | | } 217 | | None | |____________^ help: replace with an iterator: `(1..=40).map(|k| Version(k)).find(|&v| v.max_data() * 8 >= segments.iter().map(|s| s.total_size_bits(v)).sum())` | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#manual_find = note: `-D clippy::manual-find` implied by `-D warnings` = help: to override `-D warnings` add `#[allow(clippy::manual_find)]` Use `Iterator::find` instead to make the intention clearer. At the same time, clean up the redundant closure that Clippy warns about too: error: redundant closure --> drivers/gpu/drm/drm_panic_qr.rs:212:31 | 212 | for v in (1..=40).map(|k| Version(k)) { | ^^^^^^^^^^^^^^ help: replace the closure with the function itself: `Version` | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#redundant_closure = note: `-D clippy::redundant-closure` implied by `-D warnings` = help: to override `-D warnings` add `#[allow(clippy::redundant_closure)]` Fixes: cb5164ac43d0 ("drm/panic: Add a QR code panic screen") Reported-by: Miguel Ojeda <ojeda@kernel.org> Link: https://github.com/Rust-for-Linux/linux/issues/1123 Signed-off-by: Thomas Böhler <witcher@wiredspace.de> Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com> Link: https://lore.kernel.org/r/20241019084048.22336-2-witcher@wiredspace.de [ Reworded to mention the redundant closure cleanup too. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15MAINTAINERS: add entry for the Rust `alloc` moduleDanilo Krummrich
Add maintainers entry for the Rust `alloc` module. Currently, this includes the `Allocator` API itself, `Allocator` implementations, such as `Kmalloc` or `Vmalloc`, as well as the kernel's implementation of the primary memory allocation data structures, `Box` and `Vec`. Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-30-dakr@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15kbuild: rust: remove the `alloc` crate and `GlobalAlloc`Danilo Krummrich
Now that we have our own `Allocator`, `Box` and `Vec` types we can remove Rust's `alloc` crate and the `new_uninit` unstable feature. Also remove `Kmalloc`'s `GlobalAlloc` implementation -- we can't remove this in a separate patch, since the `alloc` crate requires a `#[global_allocator]` to set, that implements `GlobalAlloc`. Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-29-dakr@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15rust: alloc: update module comment of alloc.rsDanilo Krummrich
Before we remove Rust's alloc crate, rewrite the module comment in alloc.rs to avoid a rustdoc warning. Besides that, the module comment in alloc.rs isn't correct anymore, we're no longer extending Rust's alloc crate. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-28-dakr@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15rust: str: test: replace `alloc::format`Danilo Krummrich
The current implementation of tests in str.rs use `format!` to format strings for comparison, which, internally, creates a new `String`. In order to prepare for getting rid of Rust's alloc crate, we have to cut this dependency. Instead, implement `format!` for `CString`. Note that for userspace tests, `Kmalloc`, which is backing `CString`'s memory, is just a type alias to `Cmalloc`. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-27-dakr@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15rust: alloc: implement `Cmalloc` in module allocator_testDanilo Krummrich
So far the kernel's `Box` and `Vec` types can't be used by userspace test cases, since all users of those types (e.g. `CString`) use kernel allocators for instantiation. In order to allow userspace test cases to make use of such types as well, implement the `Cmalloc` allocator within the allocator_test module and type alias all kernel allocators to `Cmalloc`. The `Cmalloc` allocator uses libc's `realloc()` function as allocator backend. Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-26-dakr@kernel.org [ Removed the temporary `allow(dead_code)` as discussed in the list and fixed typo, added backticks. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15rust: alloc: implement `contains` for `Flags`Danilo Krummrich
Provide a simple helper function to check whether given flags do contain one or multiple other flags. This is used by a subsequent patch implementing the Cmalloc `Allocator` to check for __GFP_ZERO. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-25-dakr@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15rust: error: check for config `test` in `Error::name`Danilo Krummrich
Additional to `testlib` also check for `test` in `Error::name`. This is required by a subsequent patch that (indirectly) uses `Error` in test cases. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-24-dakr@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15rust: error: use `core::alloc::LayoutError`Danilo Krummrich
Use `core::alloc::LayoutError` instead of `alloc::alloc::LayoutError` in preparation to get rid of Rust's alloc crate. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-23-dakr@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15rust: alloc: add `Vec` to preludeDanilo Krummrich
Now that we removed `VecExt` and the corresponding includes in prelude.rs, add the new kernel `Vec` type instead. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-22-dakr@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15rust: alloc: remove `VecExt` extensionDanilo Krummrich
Now that all existing `Vec` users were moved to the kernel `Vec` type, remove the `VecExt` extension. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-21-dakr@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15rust: treewide: switch to the kernel `Vec` typeDanilo Krummrich
Now that we got the kernel `Vec` in place, convert all existing `Vec` users to make use of it. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-20-dakr@kernel.org [ Converted `kasan_test_rust.rs` too, as discussed. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15rust: alloc: implement `collect` for `IntoIter`Danilo Krummrich
Currently, we can't implement `FromIterator`. There are a couple of issues with this trait in the kernel, namely: - Rust's specialization feature is unstable. This prevents us to optimize for the special case where `I::IntoIter` equals `Vec`'s `IntoIter` type. - We also can't use `I::IntoIter`'s type ID either to work around this, since `FromIterator` doesn't require this type to be `'static`. - `FromIterator::from_iter` does return `Self` instead of `Result<Self, AllocError>`, hence we can't properly handle allocation failures. - Neither `Iterator::collect` nor `FromIterator::from_iter` can handle additional allocation flags. Instead, provide `IntoIter::collect`, such that we can at least convert `IntoIter` into a `Vec` again. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-19-dakr@kernel.org [ Added newline in documentation, changed case of section to be consistent with an existing one, fixed typo. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15rust: alloc: implement `IntoIterator` for `Vec`Danilo Krummrich
Implement `IntoIterator` for `Vec`, `Vec`'s `IntoIter` type, as well as `Iterator` for `IntoIter`. `Vec::into_iter` disassembles the `Vec` into its raw parts; additionally, `IntoIter` keeps track of a separate pointer, which is incremented correspondingly as the iterator advances, while the length, or the count of elements, is decremented. This also means that `IntoIter` takes the ownership of the backing buffer and is responsible to drop the remaining elements and free the backing buffer, if it's dropped. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-18-dakr@kernel.org [ Fixed typos. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15rust: alloc: implement kernel `Vec` typeDanilo Krummrich
`Vec` provides a contiguous growable array type with contents allocated with the kernel's allocators (e.g. `Kmalloc`, `Vmalloc` or `KVmalloc`). In contrast to Rust's stdlib `Vec` type, the kernel `Vec` type considers the kernel's GFP flags for all appropriate functions, always reports allocation failures through `Result<_, AllocError>` and remains independent from unstable features. [ This patch starts using a new unstable feature, `inline_const`, but it was stabilized in Rust 1.79.0, i.e. the next version after the minimum one, thus it will not be an issue. - Miguel ] Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-17-dakr@kernel.org [ Cleaned `rustdoc` unescaped backtick warning, added a couple more backticks elsewhere, fixed typos, sorted `feature`s, rewrapped documentation lines. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15rust: alloc: introduce `ArrayLayout`Benno Lossin
When allocating memory for arrays using allocators, the `Layout::array` function is typically used. It returns a result, since the given size might be too big. However, `Vec` and its iterators store their allocated capacity and thus they already did check that the size is not too big. The `ArrayLayout` type provides this exact behavior, as it can be infallibly converted into a `Layout`. Instead of a `usize` capacity, `Vec` and other similar array-storing types can use `ArrayLayout` instead. Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Benno Lossin <benno.lossin@proton.me> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-16-dakr@kernel.org [ Formatted a few comments. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15rust: alloc: add `Box` to preludeDanilo Krummrich
Now that we removed `BoxExt` and the corresponding includes in prelude.rs, add the new kernel `Box` type instead. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-15-dakr@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15rust: alloc: remove extension of std's `Box`Danilo Krummrich
Now that all existing `Box` users were moved to the kernel `Box` type, remove the `BoxExt` extension and all other related extensions. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-14-dakr@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15rust: treewide: switch to our kernel `Box` typeDanilo Krummrich
Now that we got the kernel `Box` type in place, convert all existing `Box` users to make use of it. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-13-dakr@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15rust: alloc: implement kernel `Box`Danilo Krummrich
`Box` provides the simplest way to allocate memory for a generic type with one of the kernel's allocators, e.g. `Kmalloc`, `Vmalloc` or `KVmalloc`. In contrast to Rust's `Box` type, the kernel `Box` type considers the kernel's GFP flags for all appropriate functions, always reports allocation failures through `Result<_, AllocError>` and remains independent from unstable features. Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-12-dakr@kernel.org [ Added backticks, fixed typos. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15rust: alloc: add __GFP_NOWARN to `Flags`Danilo Krummrich
Some test cases in subsequent patches provoke allocation failures. Add `__GFP_NOWARN` to enable test cases to silence unpleasant warnings. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-11-dakr@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15rust: alloc: implement `KVmalloc` allocatorDanilo Krummrich
Implement `Allocator` for `KVmalloc`, an `Allocator` that tries to allocate memory with `kmalloc` first and, on failure, falls back to `vmalloc`. All memory allocations made with `KVmalloc` end up in `kvrealloc_noprof()`; all frees in `kvfree()`. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-10-dakr@kernel.org [ Reworded typo. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15rust: alloc: implement `Vmalloc` allocatorDanilo Krummrich
Implement `Allocator` for `Vmalloc`, the kernel's virtually contiguous allocator, typically used for larger objects, (much) larger than page size. All memory allocations made with `Vmalloc` end up in `vrealloc()`. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-9-dakr@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15rust: alloc: add module `allocator_test`Danilo Krummrich
`Allocator`s, such as `Kmalloc`, will be used by e.g. `Box` and `Vec` in subsequent patches, and hence this dependency propagates throughout the whole kernel. Add the `allocator_test` module that provides an empty implementation for all `Allocator`s in the kernel, such that we don't break the `rusttest` make target in subsequent patches. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-8-dakr@kernel.org [ Added missing `_old_layout` parameter as discussed. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15rust: alloc: implement `Allocator` for `Kmalloc`Danilo Krummrich
Implement `Allocator` for `Kmalloc`, the kernel's default allocator, typically used for objects smaller than page size. All memory allocations made with `Kmalloc` end up in `krealloc()`. It serves as allocator for the subsequently introduced types `KBox` and `KVec`. Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-7-dakr@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15rust: alloc: make `allocator` module publicDanilo Krummrich
Subsequent patches implement allocators such as `Kmalloc`, `Vmalloc`, `KVmalloc`; we need them to be available outside of the kernel crate as well. Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-6-dakr@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15rust: alloc: implement `ReallocFunc`Danilo Krummrich
`ReallocFunc` is an abstraction for the kernel's realloc derivates, such as `krealloc`, `vrealloc` and `kvrealloc`. All of the named functions share the same function signature and implement the same semantics. The `ReallocFunc` abstractions provides a generalized wrapper around those, to trivialize the implementation of `Kmalloc`, `Vmalloc` and `KVmalloc` in subsequent patches. Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-5-dakr@kernel.org [ Added temporary `allow(dead_code)` for `dangling_from_layout` to clean warning in `rusttest` target as discussed in the list (but it is needed earlier, i.e. in this patch already). Added colon. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-14rust: alloc: rename `KernelAllocator` to `Kmalloc`Danilo Krummrich
Subsequent patches implement `Vmalloc` and `KVmalloc` allocators, hence align `KernelAllocator` to this naming scheme. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-4-dakr@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-14rust: alloc: separate `aligned_size` from `krealloc_aligned`Danilo Krummrich
Separate `aligned_size` from `krealloc_aligned`. Subsequent patches implement `Allocator` derivates, such as `Kmalloc`, that require `aligned_size` and replace the original `krealloc_aligned`. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-3-dakr@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-14rust: alloc: add `Allocator` traitDanilo Krummrich
Add a kernel specific `Allocator` trait, that in contrast to the one in Rust's core library doesn't require unstable features and supports GFP flags. Subsequent patches add the following trait implementors: `Kmalloc`, `Vmalloc` and `KVmalloc`. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-2-dakr@kernel.org [ Fixed typo. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-10rust: kernel: move `FromBytes` and `AsBytes` traits to a new `transmute` moduleAliet Exposito Garcia
Refactor the `FromBytes` and `AsBytes` traits from `types.rs` into a new `transmute.rs` module: - Add `rust/kernel/transmute.rs` with the definitions of `FromBytes` and `AsBytes`. - Remove the same trait definitions from `rust/kernel/types.rs`. - Update `rust/kernel/uaccess.rs` to import `AsBytes` and `FromBytes` from `transmute.rs`. The traits and their implementations remain unchanged. Suggested-by: Benno Lossin <benno.lossin@proton.me> Link: https://github.com/Rust-for-Linux/linux/issues/1117 Signed-off-by: Aliet Exposito Garcia <aliet.exposito@gmail.com> Reviewed-by: Fiona Behrens <me@kloenk.dev> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Link: https://lore.kernel.org/r/20240918225115.2309224-2-aliet.exposito@gmail.com [ Rebased on top of the lints series and slightly reworded. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-10rust: error: optimize error type to use nonzeroFilipe Xavier
Optimize `Result<(), Error>` size by changing `Error` type to `NonZero*` for niche optimization. This reduces the space used by the `Result` type, as the `NonZero*` type enables the compiler to apply more efficient memory layout. For example, the `Result<(), Error>` changes size from 8 to 4 bytes. Link: https://github.com/Rust-for-Linux/linux/issues/1120 Signed-off-by: Filipe Xavier <felipe_life@live.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Fiona Behrens <me@kloenk.dev> Link: https://lore.kernel.org/r/BL0PR02MB4914B9B088865CF237731207E9732@BL0PR02MB4914.namprd02.prod.outlook.com [ Removed unneeded block around `match`, added backticks in panic message and added intra-doc link. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-10rust: lock: add trylock method support for lock backendFilipe Xavier
Add a non-blocking trylock method to lock backend interface, mutex and spinlock implementations. It includes a C helper for spin_trylock. Rust Binder will use this method together with the new shrinker abstractions to avoid deadlocks in the memory shrinker. Link: https://lore.kernel.org/all/20240912-shrinker-v1-1-18b7f1253553@google.com Signed-off-by: Filipe Xavier <felipe_life@live.com> Reviewed-by: Fiona Behrens <me@kloenk.dev> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/BL0PR02MB4914579914884B5D7473B3D6E96A2@BL0PR02MB4914.namprd02.prod.outlook.com [ Slightly reworded. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-10rust: std_vendor: update dbg macro from Rust upstreamDeepak Thukral
`dbg!` contains adapted code from Rust upstream. Compare the kernel code with the Rust upstream one and update missing column numbers in `dbg!` outputs. Column numbers are not copied but adjusted for the kernel's examples. Suggested-by: Miguel Ojeda <ojeda@kernel.org> Link: https://github.com/Rust-for-Linux/linux/issues/1124 Signed-off-by: Deepak Thukral <iapain@gmail.com> Link: https://lore.kernel.org/r/20241004125616.49886-1-iapain@gmail.com [ Fixed typo and slightly reworded. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-07rust: error: make conversion functions publicFilipe Xavier
Change visibility to public of functions in error.rs: from_err_ptr, from_errno, from_result and to_ptr. Additionally, remove dead_code annotations. Link: https://github.com/Rust-for-Linux/linux/issues/1105 Reviewed-by: Alice Ryhl <aliceryhl@google.com> Signed-off-by: Filipe Xavier <felipe_life@live.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/DM4PR14MB7276E6948E67B3B23D8EA847E9652@DM4PR14MB7276.namprd14.prod.outlook.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-07rust: enable arbitrary_self_types and remove `Receiver`Gary Guo
The term "receiver" means that a type can be used as the type of `self`, and thus enables method call syntax `foo.bar()` instead of `Foo::bar(foo)`. Stable Rust as of today (1.81) enables a limited selection of types (primitives and types in std, e.g. `Box` and `Arc`) to be used as receivers, while custom types cannot. We want the kernel `Arc` type to have the same functionality as the Rust std `Arc`, so we use the `Receiver` trait (gated behind `receiver_trait` unstable feature) to gain the functionality. The `arbitrary_self_types` RFC [1] (tracking issue [2]) is accepted and it will allow all types that implement a new `Receiver` trait (different from today's unstable trait) to be used as receivers. This trait will be automatically implemented for all `Deref` types, which include our `Arc` type, so we no longer have to opt-in to be used as receiver. To prepare us for the change, remove the `Receiver` implementation and the associated feature. To still allow `Arc` and others to be used as method receivers, turn on `arbitrary_self_types` feature instead. This feature gate is introduced in 1.23.0. It used to enable both `Deref` types and raw pointer types to be used as receivers, but the latter is now split into a different feature gate in Rust 1.83 nightly. We do not need receivers on raw pointers so this change would not affect us and usage of `arbitrary_self_types` feature would work for all Rust versions that we support (>=1.78). Cc: Adrian Taylor <ade@hohum.me.uk> Link: https://github.com/rust-lang/rfcs/pull/3519 [1] Link: https://github.com/rust-lang/rust/issues/44874 [2] Signed-off-by: Gary Guo <gary@garyguo.net> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240915132734.1653004-1-gary@garyguo.net Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-07rust: std_vendor: simplify `{ .. macro! .. }` with inner attributesMiguel Ojeda
It is cleaner to have a single inner attribute rather than needing several hidden lines to wrap the macro invocations. Thus simplify them. Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Tested-by: Gary Guo <gary@garyguo.net> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20240904204347.168520-20-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-07Documentation: rust: discuss `#[expect(...)]` in the guidelinesMiguel Ojeda
Discuss `#[expect(...)]` in the Lints sections of the coding guidelines document, which is an upcoming feature in Rust 1.81.0, and explain that it is generally to be preferred over `allow` unless there is a reason not to use it (e.g. conditional compilation being involved). Tested-by: Gary Guo <gary@garyguo.net> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20240904204347.168520-19-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-07rust: start using the `#[expect(...)]` attributeMiguel Ojeda
In Rust, it is possible to `allow` particular warnings (diagnostics, lints) locally, making the compiler ignore instances of a given warning within a given function, module, block, etc. It is similar to `#pragma GCC diagnostic push` + `ignored` + `pop` in C: #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Wunused-function" static void f(void) {} #pragma GCC diagnostic pop But way less verbose: #[allow(dead_code)] fn f() {} By that virtue, it makes it possible to comfortably enable more diagnostics by default (i.e. outside `W=` levels) that may have some false positives but that are otherwise quite useful to keep enabled to catch potential mistakes. The `#[expect(...)]` attribute [1] takes this further, and makes the compiler warn if the diagnostic was _not_ produced. For instance, the following will ensure that, when `f()` is called somewhere, we will have to remove the attribute: #[expect(dead_code)] fn f() {} If we do not, we get a warning from the compiler: warning: this lint expectation is unfulfilled --> x.rs:3:10 | 3 | #[expect(dead_code)] | ^^^^^^^^^ | = note: `#[warn(unfulfilled_lint_expectations)]` on by default This means that `expect`s do not get forgotten when they are not needed. See the next commit for more details, nuances on its usage and documentation on the feature. The attribute requires the `lint_reasons` [2] unstable feature, but it is becoming stable in 1.81.0 (to be released on 2024-09-05) and it has already been useful to clean things up in this patch series, finding cases where the `allow`s should not have been there. Thus, enable `lint_reasons` and convert some of our `allow`s to `expect`s where possible. This feature was also an example of the ongoing collaboration between Rust and the kernel -- we tested it in the kernel early on and found an issue that was quickly resolved [3]. Cc: Fridtjof Stoldt <xfrednet@gmail.com> Cc: Urgau <urgau@numericable.fr> Link: https://rust-lang.github.io/rfcs/2383-lint-reasons.html#expect-lint-attribute [1] Link: https://github.com/rust-lang/rust/issues/54503 [2] Link: https://github.com/rust-lang/rust/issues/114557 [3] Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Trevor Gross <tmgross@umich.edu> Tested-by: Gary Guo <gary@garyguo.net> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20240904204347.168520-18-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-07Documentation: rust: add coding guidelines on lintsMiguel Ojeda
In the C side, disabling diagnostics locally, i.e. within the source code, is rare (at least in the kernel). Sometimes warnings are manipulated via the flags at the translation unit level, but that is about it. In Rust, it is easier to change locally the "level" of lints (e.g. allowing them locally). In turn, this means it is easier to globally enable more lints that may trigger a few false positives here and there that need to be allowed locally, but that generally can spot issues or bugs. Thus document this. Reviewed-by: Trevor Gross <tmgross@umich.edu> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Tested-by: Gary Guo <gary@garyguo.net> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20240904204347.168520-17-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-07rust: enable Clippy's `check-private-items`Miguel Ojeda
In Rust 1.76.0, Clippy added the `check-private-items` lint configuration option. When turned on (the default is off), it makes several lints check private items as well. In our case, it affects two lints we have enabled [1]: `missing_safety_doc` and `unnecessary_safety_doc`. It also seems to affect the new `too_long_first_doc_paragraph` lint [2], even though the documentation does not mention it. Thus allow the few instances remaining we currently hit and enable the lint. Link: https://doc.rust-lang.org/nightly/clippy/lint_configuration.html#check-private-items [1] Link: https://rust-lang.github.io/rust-clippy/master/index.html#/too_long_first_doc_paragraph [2] Reviewed-by: Trevor Gross <tmgross@umich.edu> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Tested-by: Gary Guo <gary@garyguo.net> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20240904204347.168520-16-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-07rust: provide proper code documentation titlesMiguel Ojeda
Rust 1.82.0's Clippy is introducing [1][2] a new warn-by-default lint, `too_long_first_doc_paragraph` [3], which is intended to catch titles of code documentation items that are too long (likely because no title was provided and the item documentation starts with a paragraph). This lint does not currently trigger anywhere, but it does detect a couple cases if checking for private items gets enabled (which we will do in the next commit): error: first doc comment paragraph is too long --> rust/kernel/init/__internal.rs:18:1 | 18 | / /// This is the module-internal type implementing `PinInit` and `Init`. It is unsafe to create this 19 | | /// type, since the closure needs to fulfill the same safety requirement as the 20 | | /// `__pinned_init`/`__init` functions. | |_ | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#too_long_first_doc_paragraph = note: `-D clippy::too-long-first-doc-paragraph` implied by `-D warnings` = help: to override `-D warnings` add `#[allow(clippy::too_long_first_doc_paragraph)]` error: first doc comment paragraph is too long --> rust/kernel/sync/arc/std_vendor.rs:3:1 | 3 | / //! The contents of this file come from the Rust standard library, hosted in 4 | | //! the <https://github.com/rust-lang/rust> repository, licensed under 5 | | //! "Apache-2.0 OR MIT" and adapted for kernel use. For copyright details, 6 | | //! see <https://github.com/rust-lang/rust/blob/master/COPYRIGHT>. | |_ | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#too_long_first_doc_paragraph Thus clean those two instances. In addition, since we have a second `std_vendor.rs` file with a similar header, do the same there too (even if that one does not trigger the lint, because it is `doc(hidden)`). Link: https://github.com/rust-lang/rust/pull/129531 [1] Link: https://github.com/rust-lang/rust-clippy/pull/12993 [2] Link: https://rust-lang.github.io/rust-clippy/master/index.html#/too_long_first_doc_paragraph [3] Reviewed-by: Trevor Gross <tmgross@umich.edu> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Tested-by: Gary Guo <gary@garyguo.net> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20240904204347.168520-15-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>